Studying the presence and circulation of opportunistic protozoan parasites in Leicester, UK.

A zoonotic role has been described for different opportunistic human protozoan parasites including coccidian species (Cryptosporidium spp., Cyclospora sp. and Cystoisospora sp.), Giardia intestinalis and Entamoeba histolytica. From a public health perspective, these protozoan parasites can be life threatening in immunocompromised and immunosuppressed patients. However, little is known about their presence and distribution in urban environments despite rapid development and urbanization. Our research group has detected the presence of structures related with Cryptosporidium spp., Cyclospora spp. and Giardia spp. in animal faecal samples collected in different urban parks and recreational areas in Leicester (UK) in May 2018. In these samples, either Entamoeba spp. or Cystoisospora spp. were detected. The main aim of this study was to confirm our previous results and to evaluate the potential circulation of these opportunistic pathogens in urban parks from Leicester to evaluate their risks to the population. Fifteen fresh animal faecal samples were collected in October 2018 from three frequently visited urban parks in Leicester (Castle Gardens, Victoria Park and Newalk Park). Animal droppings were collected following previous methodologies to minimize environmental contamination of the sample; a veterinarian identified the possible animal species as: 7 avian (3 waterfowl, 4 pigeon) and 8 dog/possibly fox. Kinyoun's acid-fast staining technique was used to determine the presence of coccidian oocysts and normal trichrome for the detection of Giardia spp. and Entamoeba spp. Thirty smears carefully monitored did not revealed any positive samples for these opportunistic parasites. These results might highlight a small circulation for the opportunistic parasites monitored, specifically for Cryptosporidium spp. and Giardia spp. However, our results should be considered preliminary and inconclusive, as molecular analysis of these samples and the collection of a more comprehensive number of faecal samples would be required to confirm the initial minor circulation (specifically for Cryptosporidium spp., Cyclospora spp. and Giardia spp.) and/or neglible presence (specifically for Entamoeba spp. and Cystoisospora spp.) for the opportunistic pathogens monitored. Therefore, further studies are needed to inform public regulators of potential risks to the population due to the presence/circulation of these pathogens in the Leicester’s urban media